It is known that during the turning of a screw with a screwdriver, the tip of an ordinary screwdriver with a planar blade is twisted due to the material of the tip undergoing elastic deformation. This twisting causes the tip to assume a spiral shape that results in a longitudinal force, along the screwdriver axis, pulling the screwdriver tip out from the screw spline. As a result, the edges of both operating sides of the screwdriver are rubbed out increasing the pulling effects. This destroys the screwdriver tip as well as the screw spline. This backfeed effect is illustrated in FIGS. 5a and 5b.
The present invention prevents this backfeed effect by providing a screwdriver tip which is specifically shaped such that when it is deformed during turning, the tip assumes a flat shape against the screw spline. In this manner, the screwdriver tip cannot push away from the screw spline to cause backfeed.